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RSFC44T: Fast Async RS422 to RS485 automatic converter with removable terminal strip


RSFC44T with Box

RSFC44T Label

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  • Fast RS422 to RS485 auto-TX enable interface converter for 4-wire, full-duplex (limited to half-duplex) to 2-wire, half-duplex communications, in point-to-point or multi-drop communications networks (RS485 side), at distances up to 4000 ft. and data rates up to 115.2Kbps.

General Description:

The RSFC44T is a fast Async bi-directional RS422 to RS485 interface converter for 4-wire, full-duplex (limited to half-duplex) to 2-wire, half-duplex applications, with an automatic TX enable circuit, that will operate at data rates up to 115.2Kbps. The unit has jumpers for bias and termination on the RS485 side of the interface and a setting for fast responding RS485 devices. The unit has a removable screw terminal connector, and uses an SN75LBC184P limited slew rate transceiver (1/2 unit load) with built-in transient protection (RS485 side).

The RSFC44T is designed for office and/or industrial applications (non-isolated), and provides superior characteristics/features normally found only on more expensive units. Can be used for point to point, or 4-wire RS422 (or 485) to multi-drop 2-wire systems.

Need something special? Please contact us. We have additional isolated and non-isolated converters, repeaters, and repeater hubs. Units are generally stock to 2-3 business days for shipment. We design and manufacturer our entire product line, and offer technical support for our units, and can offer system recommendations for your application. Please give us a call: 513-874-4796

Related Files:

pdf icon RSFC44TrevB.pdf Converter schematic/physical Rev. B

Physical Properties and Features:

RS422: 5-wire interface to removable screw terminal (TX+, TX-, RX+, RX-, Common)
RS485: Removable screw terminal (TX/RX+, TX/RX-, Common)
Power: 2.1mm center positive "Barrel" connector (8-12VDC), linear regulator
RS422 Bias: 620 Ohm pull-up and pull-down
RS485 Bias: 620 Ohm pull-up and pull-down (jumper selectable)
RS485 Termination: 120 Ohm (jumper selectable)
Special: Jumper selection for fast responding RS485 devices
RS485 Protection: Up to 400W typical per SN75LBC184P specification


Distance: RS422/RS485 up to 4000 ft. (1250 meters) on each side of the interface
Operation: 4-wire full-duplex (RS422/RS485) to 2-wire half-duplex RS485
Format: Asynchronous data with any combination of bits, parity, stop
Speed: Up to 115.2Kbps (slew limited driver)
Temperarure:   0-65C (32-150F) ambient
Humidity: 10-90% non-condensing
Voltage: 8-12VDC
Power: Under 1/2 Watt(typical) + external load
Size: 2.50" X 2.00" X 0.9" (PC Board), with connectors: 2.50" X 2.25"
Mounting: 4-places at 2.00" X 1.50" (built-in standoffs for #6 hardware)

Options and Ordering Information:

RSFC44T: $49.00 ea. (Circuit board only)
Enclosure: $8.00 ea. (Small)
Cable: (None- screw terminal connection only)
Supply: $8.50 ea. (12VDC @ 200/300 mA wall power supply)

*RSFC44T with all options (Enclosure/PS): RSFC44T-BSPS @ $65.50 ea. (Qty. 1-9)

Need a different configuration or more information? Give Ron a Call at 513-874-4796 or 513-638-0228(Cell)

Webstore: RSFC44T

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